IPv4 routes with IPv6 nexthop in OSPFv3
hello, it's me again, with my OSPF network. i was reading this blog post: https://ipng.ch/s/articles/2024/04/06/vpp-with-loopback-only-ospfv3-part-1/ which seems to suggest that Ondrej had done some work on advertising IPv4 prefixes into OSPFv3 with IPv6 nexthop in BIRD. however, it's not entirely clear to me how this works in practice, particularly since i don't use VPP. what i'd like to achieve is that each router that handles IPv4 packets has a single IPv4 address on lo0, and this somehow (magically) works with OSPFv3, so that i don't need to assign a /31 to every IPv4 OSPF peer. is this possible in BIRD 2.16.1, and if so, how would i go about setting it up? thanks, lexi.
On 28.02.25 6:52 PM, Lexi Winter wrote:
is this possible in BIRD 2.16.1, and if so, how would i go about setting it up?
If you use Linux you too can use unnumbered OSPF. (I did not dig yet into what VPP is or on what OS it runs...) AFAIK OSPFv3 is IPv6 only right? So in a mixed setup you need (with bird) 2 OSPF instances right? Or is this patch by now upstream? However: Unnumbered Interfaces; Like in the post, "just" assign your IPv4 /32 from `lo` to every interface where you speak OSPF. You wont get v4 via v6 NH, but you don't waste IPv4 addresses. iBGP is not an option to have v4-via-v6 routes? Best, Bernd
participants (2)
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Bernd Naumann -
Lexi Winter